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Overview
| Comment: | In the debugging memory allocator, initialize new memory allocations to pseudo-randomness in an effort to find problems with memcmp() of structures that have uninitialized pad bytes. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
6462817b2f817a6105449b0ea3e1e336 |
| User & Date: | drh 2010-01-05 03:30:15 |
Context
|
2010-01-05
| ||
| 04:59 | Fix a problem in the shell tool. In some cases sqlite3_errmsg() was being called before sqlite3_finalize(), causing error messages to be more generic than they should be. (check-in: e5d07045 user: dan tags: trunk) | |
| 03:30 | In the debugging memory allocator, initialize new memory allocations to pseudo-randomness in an effort to find problems with memcmp() of structures that have uninitialized pad bytes. (check-in: 6462817b user: drh tags: trunk) | |
| 00:14 | Fix a case in os_unix.c where two structures that might have uninitialized padding bytes are compared using memcmp(). (check-in: e02f2556 user: drh tags: trunk) | |
Changes
Changes to src/mem2.c.
205 206 207 208 209 210 211 212 213 214 215 216 217 218 ... 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 ... 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 ... 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 |
/*
** Round up a request size to the next valid allocation size.
*/
static int sqlite3MemRoundup(int n){
return ROUND8(n);
}
/*
** Allocate nByte bytes of memory.
*/
static void *sqlite3MemMalloc(int nByte){
struct MemBlockHdr *pHdr;
void **pBt;
................................................................................
if( mem.nTitle ){
memcpy(z, mem.zTitle, mem.nTitle);
}
pHdr->iSize = nByte;
adjustStats(nByte, +1);
pInt = (int*)&pHdr[1];
pInt[nReserve/sizeof(int)] = REARGUARD;
memset(pInt, 0x65, nReserve);
p = (void*)pInt;
}
sqlite3_mutex_leave(mem.mutex);
return p;
}
/*
................................................................................
}else{
assert( mem.pLast==pHdr );
mem.pLast = pHdr->pPrev;
}
z = (char*)pBt;
z -= pHdr->nTitle;
adjustStats(pHdr->iSize, -1);
memset(z, 0x2b, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
pHdr->iSize + sizeof(int) + pHdr->nTitle);
free(z);
sqlite3_mutex_leave(mem.mutex);
}
/*
** Change the size of an existing memory allocation.
**
................................................................................
void *pNew;
assert( mem.disallow==0 );
pOldHdr = sqlite3MemsysGetHeader(pPrior);
pNew = sqlite3MemMalloc(nByte);
if( pNew ){
memcpy(pNew, pPrior, nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize);
if( nByte>pOldHdr->iSize ){
memset(&((char*)pNew)[pOldHdr->iSize], 0x2b, nByte - pOldHdr->iSize);
}
sqlite3MemFree(pPrior);
}
return pNew;
}
/*
|
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/*
** Round up a request size to the next valid allocation size.
*/
static int sqlite3MemRoundup(int n){
return ROUND8(n);
}
/*
** Fill a buffer with pseudo-random bytes. This is used to preset
** the content of a new memory allocation to unpredictable values and
** to clear the content of a freed allocation to unpredictable values.
*/
static void randomFill(char *pBuf, int nByte){
unsigned int x, y, r;
x = SQLITE_PTR_TO_INT(pBuf);
y = nByte | 1;
while( nByte >= 4 ){
x = (x>>1) ^ (-(x&1) & 0xd0000001);
y = y*1103515245 + 12345;
r = x ^ y;
*(int*)pBuf = r;
pBuf += 4;
nByte -= 4;
}
while( nByte-- > 0 ){
x = (x>>1) ^ (-(x&1) & 0xd0000001);
y = y*1103515245 + 12345;
r = x ^ y;
*(pBuf++) = r & 0xff;
}
}
/*
** Allocate nByte bytes of memory.
*/
static void *sqlite3MemMalloc(int nByte){
struct MemBlockHdr *pHdr;
void **pBt;
................................................................................
if( mem.nTitle ){
memcpy(z, mem.zTitle, mem.nTitle);
}
pHdr->iSize = nByte;
adjustStats(nByte, +1);
pInt = (int*)&pHdr[1];
pInt[nReserve/sizeof(int)] = REARGUARD;
randomFill((char*)pInt, nByte);
memset(((char*)pInt)+nByte, 0x65, nReserve-nByte);
p = (void*)pInt;
}
sqlite3_mutex_leave(mem.mutex);
return p;
}
/*
................................................................................
}else{
assert( mem.pLast==pHdr );
mem.pLast = pHdr->pPrev;
}
z = (char*)pBt;
z -= pHdr->nTitle;
adjustStats(pHdr->iSize, -1);
randomFill(z, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
pHdr->iSize + sizeof(int) + pHdr->nTitle);
free(z);
sqlite3_mutex_leave(mem.mutex);
}
/*
** Change the size of an existing memory allocation.
**
................................................................................
void *pNew;
assert( mem.disallow==0 );
pOldHdr = sqlite3MemsysGetHeader(pPrior);
pNew = sqlite3MemMalloc(nByte);
if( pNew ){
memcpy(pNew, pPrior, nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize);
if( nByte>pOldHdr->iSize ){
randomFill(&((char*)pNew)[pOldHdr->iSize], nByte - pOldHdr->iSize);
}
sqlite3MemFree(pPrior);
}
return pNew;
}
/*
|